CN113015637A

CN113015637A - Cooling circuit for a vehicle

Info

Publication number: CN113015637A
Application number: CN201980070603.XA
Authority: CN
Inventors: M.雅希亚
Original assignee: Valeo Systemes Thermiques SAS
Current assignee: Valeo Systemes Thermiques SAS
Priority date: 2018-09-26
Filing date: 2019-09-26
Publication date: 2021-06-22
Also published as: EP3856555A1; US11679642B2; JP2022501252A; KR102480203B1; EP3856555B1; FR3086334A1; JP7198916B2; US20220048358A1; WO2020065230A1; KR20210064309A; FR3086334B1

Abstract

The invention relates to a circuit (1) for a coolant (47), comprising a main pipe (3), a first branch (4), a second branch (5) and a third branch (25), the main pipe (3) comprising a compression device (2) and a main heat exchanger (8), the main heat exchanger (8) being arranged to be crossed by an external air flow (EF), the first branch (4) comprising a first heat exchanger (13) and an accumulation device (15) thermally coupled to a loop (14) for a heat transfer liquid (48), the second branch (5) comprising a second heat exchanger (17), the third branch (25) comprising a third heat exchanger (26), characterized in that the first branch (4) and the second branch (5) are connected in parallel and meet at a convergence point (6), the first branch (4) and the third branch (25) meeting at a first junction point (19). Use in a motor vehicle.

Description

Cooling circuit for a vehicle

Technical Field

The field of the invention is refrigerant circuits for vehicles, in particular for motor vehicles.

Background

Currently, motor vehicles are equipped with a refrigerant circuit for heating or cooling various zones or various components of the vehicle. It is a particularly known practice for the refrigerant circuit to be used for the thermal treatment of an air flow fed into the interior of a vehicle equipped with such a circuit.

In another application of this circuit, it is known practice to use the circuit to cool a portion of the electric traction drive system of a vehicle. This part is in particular an accumulator device for supplying electric power to an electric motor enabling the vehicle to run. Thus, when the refrigerant circuit is used in the driving phase, the refrigerant circuit provides energy capable of cooling the electrical storage device. Therefore, the refrigerant circuit is designed to cool the electrical storage device to maintain a moderate temperature.

It is also known practice to charge the electric storage device of a vehicle by connecting it to the domestic electric network for hours. This long-term charging technique allows the temperature of the electrical storage device to be kept below a certain threshold, so that any system for cooling the electrical storage device can be omitted.

A new fast charging technique has recently been developed. It involves charging an electrical storage device with high voltage and current so as to charge the electrical storage device in a short time of several minutes. This rapid charging causes the electrical storage device to heat up, requiring it to be cooled. This heating control part is rated as this is the most severe case. This rated value has a large influence on normal operation other than rapid charging, particularly due to overheating occurring downstream of the cooler of the electrical storage device.

The technical problem is therefore that of the ability, on the one hand, to dissipate the thermal energy generated by a portion of the electric traction drive system of the vehicle and, on the other hand, to cool the interior of the vehicle while maintaining a level of circuit performance considered acceptable.

Disclosure of Invention

The present invention is under such circumstances and proposes a technical solution that seeks to achieve this object, namely to keep the electrical storage device below a threshold temperature and/or to cool the vehicle interior to a given performance level, by means of a refrigerant circuit that is cleverly designed to operate with two heat exchangers dedicated to cooling a portion of the electric traction drive system of the vehicle and a third heat exchanger dedicated to cooling the vehicle interior, so that overheating at the inlet of the compression device can be achieved in a simple and economical manner.

One subject of the invention is therefore a refrigerant circuit for a vehicle, the circuit comprising at least a main pipe, a first branch, a second branch and a third branch, all three branches being connected in series with the main pipe, the main pipe comprising at least a compression device for compressing refrigerant and a main heat exchanger arranged to pass an external air flow outside the vehicle interior, the first branch comprising at least a first heat exchanger thermally coupled to a heat transfer liquid loop and an accumulation device for accumulating refrigerant, the second branch comprising at least a second heat exchanger thermally coupled to a heat transfer fluid loop, the third branch comprising at least a third heat exchanger designed to pass an internal air flow sent to the vehicle interior through it, characterized in that the first branch and the second branch are connected in parallel and meet at a convergence point located between the accumulation device and the compression device, and the first branch and the third branch meet at a first junction between the first heat exchanger and the accumulating device. The first heat exchanger and the third heat exchanger are intended to supply refrigerant to the accumulation device, while the second heat exchanger is connected in such a way as to bypass the accumulation device. The second heat exchanger is in fact connected downstream of the accumulation device from the point of view of the refrigerant. The second heat exchanger is capable of producing superheat in the refrigerant. The refrigerant is in gaseous form when superheated. Thus, the gaseous refrigerant from the second heat exchanger directly reaches the compression device, which helps to improve the coefficient of performance of the circuit. By "directly" is meant that there is no bottle or accumulator between the second heat exchanger and the compression device.

When the first heat exchanger and the second heat exchanger are operated together, refrigerant from the accumulator close to a saturated vapor state (in particular, close to a vapor content of 0.95) and superheated gaseous refrigerant directly from the second heat exchanger are collected in the main pipe at a collection point. Thus, the refrigerant is mixed and moderately superheated. This overheating results in an overall improvement in the loop coefficient of performance.

The first heat exchanger is connected upstream of the accumulating device and the second heat exchanger is connected downstream of the accumulating device from the viewpoint of the refrigerant, which means that the operation of the accumulating device can be separated from the operation of the third heat exchanger, for example, during highway driving, moderate cooling of the electrical storage device is much lower than the maximum cooling capacity during rapid charging. Without such an arrangement, the circuit could be operated to flood the first heat exchanger to compensate for overheating of the second heat exchanger, although this complicates the optimisation and control means.

The first heat exchanger is configured to thermally treat at least a portion of an electric traction drive system of a vehicle, such as an electric storage device and/or an electronic unit and/or the electric motor itself for powering an electric motor capable of moving the vehicle. Thus, the first heat exchanger operates as an evaporator.

The second heat exchanger is configured to thermally treat at least a portion of an electric traction drive system of a vehicle, such as an electric storage device and/or an electronic unit and/or an electric motor for powering an electric motor capable of moving the vehicle. Thus, the second heat exchanger operates as an evaporator.

Advantageously, the first heat exchanger and the second heat exchanger are assigned to the thermal treatment of the same part of the electric traction drive system of the vehicle, for example the electric storage device.

The first heat exchanger and the second heat exchanger each allow thermal energy exchange between the refrigerant and a portion of the electric traction drive system of the vehicle, or directly, i.e. by convection between the first heat exchanger and the portion of the electric traction drive system of the vehicle, and/or between the second heat exchanger and the portion of the electric traction drive system of the vehicle. In this case, the cooling of the elements of the electric traction drive system of the vehicle is direct. Alternatively, the exchange of thermal energy may be carried out indirectly via a heat transfer liquid loop intended to transfer thermal energy from a portion of the electric traction drive system of the vehicle to the first heat exchanger and/or the second heat exchanger. Thus, it should be understood that cooling of elements of the electric traction drive system of the vehicle may be indirect.

The first heat exchanger and the second heat exchanger are each independent, that is, they may be located at different locations in the vehicle, physically remote from each other.

The third heat exchanger may be installed in a ventilation, heating and/or air conditioning apparatus. The third heat exchanger may thus act as an evaporator in order to cool the air flow sent into the vehicle interior.

The first junction is the convergence point of the loop. The refrigerant from the first heat exchanger and the third heat exchanger may converge at a first junction point.

The compression device is, for example, a compressor, and the invention is particularly applicable when the compressor is a variable speed electric compressor of fixed cylinder capacity. The thermal power of the circuit according to the invention can thus be controlled.

The main heat exchanger may act as a condenser. It is located on the front face of the vehicle in order to benefit from the supply of outside air flow during the driving phase. The main heat exchanger may act as an evaporator when the circuit is capable of operating as a heat pump.

The refrigerant is, for example, a subcritical fluid, as known by reference to R134A or R1234 yf. The refrigerant circuit according to the invention is a closed circuit implementing a thermodynamic cycle.

From a refrigerant perspective, the first and second legs of the circuit are in parallel. From a refrigerant perspective, both the first and second legs of the circuit are in series with the main tube.

According to one aspect of the invention, the main pipe extends between a convergence point and a bifurcation point, the bifurcation point being the point at which the first leg and the second leg diverge.

In accordance with one aspect of the invention, the main pipe includes a subcooling unit located between the main heat exchanger and the bifurcation point. The main heat exchanger is associated with a refrigerant subcooling unit. The subcooling unit is capable of producing subcooling of the refrigerant, i.e., reducing the temperature of the refrigerant below its condensation temperature.

According to one aspect of the invention, the subcooling unit is a fourth heat exchanger designed to pass an external air stream outside the vehicle interior through it and mounted so that the external air stream passes through it before it passes through the main heat exchanger. The supercooling unit can therefore be located on the front face of the vehicle together with the main heat exchanger in order to benefit from the supply of the external air stream during the driving phase. The external air stream first passes through the subcooling unit. Then, upon exiting the subcooling unit, the external air stream passes through the main heat exchanger.

When both the subcooling unit and the main heat exchanger are used to cool the refrigerant, the external air stream is sequentially subjected to a first heat exchange with the subcooling unit and then a second heat exchange with the main heat exchanger.

According to one aspect of the invention, the first branch comprises a first junction point, the second branch comprises a second junction point, and the third branch of the loop extends between the first junction point and the second junction point.

The second junction is the bifurcation of the circuit. The refrigerant from the main pipe may be branched off at the second junction point to be supplied to the second heat exchanger and the third heat exchanger.

The third branch is connected in parallel with at least a first portion of the first branch, the first portion of the first branch comprising at least the first heat exchanger, the second portion of the first branch comprising at least the accumulating means.

According to one aspect of the invention, the primary pipe comprises a primary expansion member. The main expansion means is located upstream of the main heat exchanger from a refrigerant perspective. When the main heat exchanger is operating as a condenser, the main expansion device is not operating. It is therefore fully open. When the main heat exchanger operates as an evaporator, the main expansion member expands the refrigerant.

According to one aspect of the invention, the first branch comprises a first expansion member. The first expansion member is upstream of the first heat exchanger from a refrigerant perspective.

According to one aspect of the invention, the second branch comprises a second expansion member. The second expansion member is upstream of the second heat exchanger from a refrigerant perspective.

According to one aspect of the invention, the third branch comprises a third expansion member. The third expansion member is upstream of the third heat exchanger from a refrigerant perspective.

The main expansion member, the first expansion member, the second expansion member and/or the third expansion member is an electronic expansion valve, for example. They may be equipped with a cut-off function. When the shut-off function is not part of one and/or the other of the expansion members, the shut-off function is offset upstream of the relative expansion member and is performed by a dedicated component.

One and/or the other of these expansion members may be fully or partially open. When open, they do not change the state of the refrigerant flowing through them: they are then considered to be inoperative and fully open. When they are closed, they prevent the refrigerant from passing. When they are partially open, they expand the refrigerant, thereby affecting the refrigeration power provided by the associated heat exchanger.

According to one aspect of the invention, the accumulation device is located between the first junction point and the convergence point. Thus, the accumulating means may be supplied by the first heat exchanger and/or the third heat exchanger and/or the main heat exchanger.

According to one aspect of the invention, the main pipe comprises a fifth heat exchanger located between the compression device and the main heat exchanger, the fifth heat exchanger being designed to pass through it the internal air stream sent to the interior of the vehicle. The fifth heat exchanger may be installed in a heating, ventilating and/or air conditioning apparatus. The fifth heat exchanger functions as a condenser to heat the air stream sent into the vehicle interior. Thus, the fifth heat exchanger may be installed in a heating, ventilating and/or air conditioning apparatus together with the third heat exchanger. When there is a fifth heat exchanger operating as a condenser, the main heat exchanger can operate as an evaporator in the heat pump mode.

According to one aspect of the invention, the main pipe comprises a third junction point between the main heat exchanger and the bifurcation point, and the fourth branch extends between the third junction point and the first junction point, the fourth branch comprising at least one shut-off valve. The third junction is the bifurcation of the circuit. The shutoff valve may be opened or closed, allowing or not allowing refrigerant to circulate in the fourth branch passage. The first junction point is a convergence point of the refrigerants from the fourth branch, the first heat exchanger and the third heat exchanger.

According to one aspect of the invention, the third junction point is located between the main heat exchanger and the subcooling unit. Refrigerant from the main heat exchanger may be tapped at a third junction point to feed a fourth branch and thus to the first junction point, the accumulating device and the subcooling unit.

According to one aspect of the invention, the circuit comprises a fifth branch connecting the main pipe to the bifurcation point, the fifth branch comprising at least one shut-off valve. The shutoff valve may be opened or closed to allow or disallow refrigerant to circulate in the fifth branch.

The fifth branch extends between a fourth junction point in the main pipe between the fifth heat exchanger and the main heat exchanger and a bifurcation point. Advantageously, the fourth junction point is located between the fifth heat exchanger and the main expansion member. Therefore, when the main expansion member is closed, the refrigerant passes through the fifth branch to reach the branch point of the circuit.

According to one aspect of the invention, the first heat exchanger is configured to generate a thermal power greater than a thermal power of the second heat exchanger. The first heat exchanger and the second heat exchanger have different thermal properties. This difference may result from the fact that the first heat exchanger and the second heat exchanger are different models, for example in terms of size, shape and/or use of techniques and/or material designs that give them different thermal performance characteristics. For example, the first heat exchanger is configured for a higher refrigerant flow rate. According to another example, wherein the heat exchangers are identical plate heat exchangers, the first heat exchanger has more plates than the second heat exchanger.

The first heat exchanger and/or the second heat exchanger are used in dependence on the cooling demand of the part of the electric traction drive system being cooled by the heat transfer liquid loop. During the driving phase, the cooling demand is low, so the second heat exchanger is used. During the fast charge phase, the first heat exchanger provides the majority of the required power. The second heat exchanger provides support and allows for a superheated operating point at the inlet of the compression device, thus improving the operating cycle.

According to one aspect of the invention, the circuit includes an internal heat exchanger having two channels, a low pressure channel being located in the main pipe between the convergence point and the compression device, and a high pressure channel being located in the main pipe between the subcooling unit and the bifurcation point.

According to an alternative aspect of the invention, the circuit includes an internal heat exchanger having two channels, a low pressure channel located between the accumulator and the point of convergence, and a high pressure channel located in the main pipe between the subcooling unit and the point of divergence.

The invention also relates to a system for the thermal treatment of a vehicle, comprising a refrigerant circuit for a refrigerant as described above and a heat transfer liquid loop thermally coupled to the refrigerant circuit via a first heat exchanger and a second heat exchanger, the first heat exchanger and the second heat exchanger being assigned to the thermal treatment of at least one same part of an electric traction drive system of the vehicle.

The heat transfer liquid loop is a closed circuit comprising at least a main pipe, a first heat exchanger and a second heat exchanger, and a circulation-inducing device, such as a pump, capable of circulating the heat transfer liquid in the main pipe.

Thus, the first heat exchanger and the second heat exchanger form part of a refrigerant circuit and a heat transfer liquid loop. These are two-fluid, in particular two-liquid heat exchangers configured to have both refrigerant and heat transfer liquid passing through them. In the first heat exchanger on the one hand and in the second heat exchanger on the other hand, there is a thermal energy transfer between the refrigerant and the heat transfer liquid: when the first heat exchanger and/or the second heat exchanger operate as an evaporator, the heat transfer liquid is cooled.

Part of the electric traction drive system of a vehicle is for example an electric storage device of the vehicle, such as a battery or a battery pack. The portion of the electric traction drive system may also correspond to an electric traction motor of the vehicle, or to an electronic control unit of the electric traction motor. In other words, the portion may correspond to any portion of the electric traction drive system of the vehicle that needs to be cooled. Heat treatment may also be directed to many of these components.

Drawings

Further features, details and advantages of the invention will become more apparent from reading the following description, provided for informational purposes, with reference to the accompanying drawings, in which:

fig. 1 is a schematic view of a circuit according to the invention in a first embodiment;

fig. 2 to 6 show a circuit as subject of a first embodiment, operating according to different operating modes including cooling the interior of the vehicle and/or a portion of the electric traction drive system of the vehicle;

fig. 7 is a schematic view of a circuit according to the invention in a second embodiment.

Detailed Description

It should be noted at the outset that the drawings illustrate the invention in detail for the purpose of practicing the invention, and of course, may be used to better define the invention, if necessary. These figures are schematic diagrams illustrating how the circuit is constructed, what the circuit is made up of and how refrigerant circulates through the circuit. In particular, the circuit according to the invention essentially comprises means for compressing the refrigerant, two heat exchangers coupled to the heat transfer liquid circuit, two heat exchangers in exchange with air, at least three expansion members and a tube connecting each of these components.

The terms upstream and downstream as used in the following description refer to the direction of circulation of the fluid in question, i.e. the refrigerant, the internal air flow sent to the interior of the vehicle or the external air flow sent to the interior of the vehicle.

In fig. 2 to 6, the refrigerant is represented by arrows showing the direction of circulation of the refrigerant in the tube in question. The solid line shows a portion of the circuit in which the refrigerant circulates, while the dashed line shows no circulation of the refrigerant. The high-pressure, high-temperature refrigerant is indicated by solid arrows. The low pressure, low temperature refrigerant is indicated by the dashed arrows.

The identifiers "primary," "first," "second," etc. are not intended to indicate a hierarchy or order of its accompanying terms. These identifiers are used to distinguish the terms they accompany and are interchangeable without affecting the scope of the present invention.

Thus, fig. 1 shows a circuit 1 according to a first embodiment. The circuit 1 is a closed loop circuit in which the refrigerant circulates through the second compression means 2. It should be noted that the compression device 2 may take the form of an electric compressor, that is to say a compressor comprising a compression mechanism, an electric motor and possibly a controller.

According to the first embodiment shown, the circuit 1 comprises at least a main pipe 3, a first branch 4 and a second branch 5. The first branch 4 and the second branch 5 are both connected in series with the main pipe 3. The first branch 4 and the second branch 5 are parallel and meet at a convergence point 6. The main pipe 3 extends between a convergence point 6 and a divergence point 7, the divergence point 7 being the point at which the first branch 4 and the second branch 5 diverge.

The main pipe 3 comprises at least a refrigerant compression device 2 and a main heat exchanger 8. The main heat exchanger 8 is designed to pass an external air stream located outside the vehicle interior through the main heat exchanger. Therefore, the main heat exchanger 8 is located on the front face of the vehicle so as to be supplied with the outside air stream. The main heat exchanger 8 can operate as a condenser.

The main pipe 3 comprises a main expansion member 9. From a refrigerant point of view, it is located upstream of the main heat exchanger 8. Thus, in association with the main expansion means 9, the main heat exchanger 8 is able to operate as an evaporator. The primary expansion member 9 may be fully open or partially open or closed, with a shut-off function incorporated therein.

The main pipe 3 includes a subcooling unit 10 between the main heat exchanger 8 and the branch point 7. The supercooling unit 10 is a fourth heat exchanger. The supercooling unit 10 is located on a front face of the vehicle, and thus is supplied with an external air flow. Therefore, the main heat exchanger 8 and the subcooling unit 10 are located together at the front of the vehicle. The subcooling unit 10 is installed such that the external air stream passes through it before passing through the main heat exchanger 8. From the point of view of the external air stream, the fourth heat exchanger is upstream of the main heat exchanger 8.

The main pipe 3 comprises a non-return valve 11. A check valve 11 is located between the subcooling unit 10 and the bifurcation 7. The check valve 11 prevents the refrigerant from flowing from the branch point 7 to the supercooling unit 10.

The main pipe 3 comprises a first heat exchanger 12 which is located between the compression means 2 and the main heat exchanger 8. In this example, the fifth heat exchanger 12 is located between the compression device 2 and the main expansion member 9. The fifth heat exchanger 12 is designed to pass therethrough an internal air flow sent into the vehicle interior. It is configured to operate as a condenser in a heating, ventilation and/or air conditioning apparatus.

The first branch 4 comprises at least a first heat exchanger 13 thermally coupled to a heat transfer liquid loop 14 and an accumulation device 15 for accumulating refrigerant.

The first heat exchanger 13 is configured to operate as an evaporator. The first heat exchanger 13 is associated with a first expansion member 16 located upstream of the first heat exchanger 13. The primary expansion member 16 may be fully open or partially open or closed, with a shut-off function incorporated therein.

From the point of view of the refrigerant, the accumulation means 15 are upstream of the point of convergence 6. The accumulation device 15 can separate the liquid phase from the gas phase of the refrigerant, and can accumulate the liquid phase of the refrigerant. Thus, the circuit 1 has no desiccant bottle.

The second branch 5 comprises at least a second heat exchanger 17, the second heat exchanger 17 being thermally coupled to the heat transfer liquid loop 14. The second heat exchanger 17 is configured to operate as an evaporator. The second heat exchanger 17 is associated with a second expansion member 18 located upstream of the second heat exchanger 17. The second expansion member 18 may be fully open or partially open or closed, which incorporates a shut-off function.

The conditions of use of the heat transfer liquid loop 14 may produce superheating of the refrigerant in the second heat exchanger 17. For the same pressure, this superheat corresponds to the temperature of the refrigerant rising above its saturation temperature.

The convergence point 6 is located between the accumulation means 15 and the compression means 2. Therefore, the refrigerant can be supplied to the accumulator 15 through the first heat exchanger 13 instead of the second heat exchanger 17.

The first heat exchanger 13 is configured to generate a thermal power greater than that of the second heat exchanger 17. For example, the first heat exchanger 13 is larger in size than the second heat exchanger 17.

The first branch 4 comprises a first junction 19, the second branch 5 comprises a second junction 20, and a third branch 25 of the circuit 1 extends between the first junction 19 and the second junction 20.

The first branch 4 is divided into a first section 21 and a second section 22. The first portion 21 extends from the bifurcation point 7 to the first junction point 19. The second portion 22 extends from the first junction 19 to the convergence point 6. The first expansion member 16 and the first heat exchanger 13 are included in the first portion 21 of the first branch 4. The accumulation means 15 are themselves comprised in the second portion 22 of the first branch 4.

The second branch 5 is divided into a first section 23 and a second section 24. The first section 23 extends between the bifurcation point 7 and the second junction 20. The second section 24 extends between the second junction point 20 and the convergence point 6. The second expansion means 18 and the second heat exchanger 17 are comprised in the second section 24 of the second branch 5.

The third branch 25 comprises at least a third heat exchanger 26, through which the third heat exchanger 26 is designed to pass the internal air flow sent into the vehicle interior. The third heat exchanger 26 is configured to operate as an evaporator in a vehicle equipped heating, ventilation and/or air conditioning apparatus 27. The third heat exchanger 26 is associated with a third expansion member 28 located upstream of the third heat exchanger 26. The third expansion member 28 may be fully open or partially open or closed.

The third heat exchanger 26 is located in a heating, ventilating and/or air conditioning apparatus 27 together with the fifth heat exchanger 12. For example, the third heat exchanger 26 is located upstream of the fifth heat exchanger 12 from the perspective of the internal air flow.

The third heat exchanger 26 is able to supply refrigerant to an accumulation device 15 located downstream of the third heat exchanger 26, between the first junction point 19 and the convergence point 6.

The circuit is configured such that the first heat exchanger 13 operates alone. The second expansion member 18 and the third expansion member 28 are then closed.

The main pipe 3 includes a third junction 29 between the main heat exchanger 8 and the first junction 19, and a fourth branch 30 extends between the third junction 29 and the first junction 19. The main heat exchanger 8 is able to supply refrigerant to the accumulating means 15 via a fourth branch 30.

The fourth branch 30 comprises at least one shut-off valve 31. The shutoff valve 31 allows the refrigerant to flow in the fourth branch passage 30 when opened, and prevents the flow when closed.

The circuit 1 comprises a fifth branch 32, which fifth branch 32 connects the main pipe 3 to the bifurcation point 7.

The fifth branch 32 extends between the fourth junction 33 and the bifurcation point 7. The fourth junction point 33 is located in the main pipe 3 between the fifth heat exchanger 12 and the main heat exchanger 8. Advantageously, the fourth junction point 33 is located between the fifth heat exchanger 12 and the main expansion member 9.

The fifth branch 32 comprises at least one shut-off valve 34. When the shutoff valve 34 is open, the refrigerant is allowed to circulate in the fifth branch passage 32, and when closed, the circulation is blocked.

The main tube 3 is divided into a first section 35, a second section 36 and a third section 37. The first portion 35 extends between the convergence point 6 and the fourth junction point 33. The compression device 2 and the fifth heat exchanger 12 are included in the first portion 35 of the main pipe 3. A second branch 36 extends between the fourth junction 33 and the third junction 29. Main expansion means 9 and main heat exchanger 8 are included in second portion 36 of main pipe 3. The third portion 37 extends between the third junction 29 and the bifurcation point 7. The supercooling unit 10 and the check valve 11 are included in the third portion 37 of the main pipe 3.

The refrigerant circuit 1 is comprised in a heat treatment system 38 of a vehicle. The heat treatment system 38 comprises a refrigerant circuit 1 and a heat transfer liquid loop 14. The heat transfer liquid loop 14 and the refrigerant circuit 1 are thermally coupled via a first heat exchanger 13 and a second heat exchanger 17.

The first heat exchanger 13 and the second heat exchanger 17 are assigned to the thermal treatment of at least one identical part 39 of the electric traction drive system of the vehicle. In the example of fig. 1, the first heat exchanger 13 and the second heat exchanger 17 are assigned to the heat treatment of the electrical storage device 40 of the vehicle.

The heat transfer liquid loop 14 is a closed circuit 1 comprising at least a main pipe 41, a first heat exchanger 13 and a second heat exchanger 17 and a circulation inducing means 42. In the example of fig. 1, the heat transfer liquid loop 14 includes a second conduit 44, a first conduit 43, and a main conduit 41 extending between a first connection point 45 and a second connection point 46. From the point of view of the heat transfer liquid, the main pipe 41 is in series with a first duct 43 and a second duct 44. From the same point of view, the first duct 43 and the second duct 44 are connected in parallel with each other.

The main pipe 41 includes an electrical storage device 40 and a circulation inducing means 42. The electrical storage device 40 is located between the second connection point 46 and the flow-through inducing means 42. The first conduit 43 includes the first heat exchanger 13. The second conduit 44 includes the second heat exchanger 17.

The circulation inducing means 42 is capable of circulating the heat transfer liquid in the main pipe 41. For example, the flow-through inducing means 42 is a pump.

Fig. 2 to 6 show a circuit 1 according to the invention in the embodiment shown in fig. 1. Fig. 2 to 6 correspond to various cases where heat treatment is required for the interior of the vehicle and/or the power storage device 40. The required cooling power varies depending on the provided operating mode. As a result, one and/or the other of the heat exchanger or the fifth heat exchanger 12 is required.

Fig. 2 shows a circuit 1 according to the invention, which is used in an air-conditioning mode and which thermally treats an electrical storage device 40 during a driving phase. This operation mode allows the vehicle interior and the electrical storage device 40 to be cooled simultaneously. The cooling of the interior is performed by the third heat exchanger 26. The cooling of the electrical storage device 40 is performed only by the second heat exchanger 17.

In the example of fig. 2, the compression device 2 applies high pressure and high temperature to the refrigerant 47 in the main pipe 3. In this state, the refrigerant 47 passes through the fifth heat exchanger 12, and thus is not used.

The refrigerant 47 passes through the fourth junction point 33 to enter the second portion 36 of the main tube 3, and the shutoff valve 34 is then closed to prevent it from passing through the fifth branch 32.

In the second portion 36 of the main pipe 3, the refrigerant 47 passes through the main expansion member 9 which is fully opened. Thus, it does not undergo any expansion therein.

In the example of fig. 2, the main heat exchanger 8 operates as a condenser. Through which the external air stream FE passes, at least a portion of which has previously passed through the subcooling unit 10. Refrigerant 47 transfers thermal energy to outside air stream FE and condenses. Outside the main heat exchanger 8, the refrigerant 47 passes through the third junction point 29 and reaches the third portion 37 of the main pipe 3, the shut-off valve 31 being closed. It undergoes supercooling while passing through the supercooling unit 10, and the supercooling unit 10 simultaneously passes the external air stream FE therethrough.

Next, the refrigerant 47 passes through the check valve 11 to the branch point 7. Since the first expansion member 16 is closed, the refrigerant 47 enters the second branch 5 and the third branch 25, and the second expansion member 18 and the third expansion member 28 allow the refrigerant to pass therethrough since they are partially opened.

In the second branch 5, the refrigerant 47 at high pressure and high temperature undergoes expansion by the second expansion member 18. It passes through the second heat exchanger 17 at low pressure and temperature. In this way, the refrigerant 47 exchanges heat with the loop 14 for the heat transfer liquid 48 in the second heat exchanger 17 to cool the heat transfer liquid 48. The thermal conditions imposed by the portion of the electric traction drive system 39 allow the refrigerant 47 to superheat, so the refrigerant 47 is entirely in the vapor phase. It is in this superheated state that refrigerant 47 reaches convergence point 6.

In the third branch 25, the refrigerant 47 at high pressure and high temperature undergoes expansion by the third expansion member 28. It passes through the third heat exchanger 26 at low pressure and temperature. In this way, the refrigerant 47 exchanges heat with an internal air flow FA intended for the vehicle interior. Upon exiting third heat exchanger 26, refrigerant 47 is in two-phase form. Within the accumulation means 15, the liquid phase is separated and reaches the point of convergence 6, substantially in gas phase.

At the convergence point 6, the superheated refrigerant 47 from the second branch 5 and the refrigerant 47 from the third branch 25 reach the compression device 2 at moderate superheat, completing the thermodynamic cycle at the compression device 2.

In the example of fig. 2, the refrigerant 47 circulates through the entire main pipe 3, the second branch passage 5, and the third branch passage 25. It does not circulate in the first branch 4 due to the closing of the first expansion member 16, it does not circulate in the fourth branch 30 due to the closing of the shut-off valve 31, and it does not circulate in the fifth branch 32 due to the closing of the shut-off valve 34. The second joining point 20 is a point at which the refrigerant 47 is branched, and the merging point 6 is a point at which the refrigerant 47 is merged.

In the example of fig. 2, a heat transfer liquid 48 circulates at least in the main pipe 41 and the second pipe 44 in order to cool a portion 39 of the electric traction drive system, such as the electrical storage device 40.

Fig. 3 shows that during a driving phase, the circuit 1 according to the invention operates exclusively in air-conditioning mode. This mode of operation allows cooling of the vehicle interior by using the third heat exchanger 26 of the heating, ventilation and/or air conditioning device 27.

Differences compared to those described in fig. 2 will be described below. In addition to these differences, the description of fig. 2 applies mutatis mutandis and reference may be made to the implementation of the invention described in fig. 3.

In the example of fig. 3, the first expansion member 16 and the second expansion member 18 are closed. As a result, the refrigerant 47 does not flow through the second section 24 of the second branch passage 5. At the second junction point 20 it only uses the second branch 25. The convergence point 6 does not receive superheated refrigerant 47 from the second branch 5.

In the example of fig. 3, the refrigerant 47 circulates through the entire main pipe 3, the first section 23 of the second branch passage 5, and the third branch passage 25. It does not circulate in the first branch 4 due to the closure of the first expansion member 16, it does not circulate in the second section 24 of the second branch 5 due to the closure of the second expansion member 18, it does not circulate in the fourth branch 30 due to the closure of the shut-off valve 31, and it does not circulate in the fifth branch 32 due to the closure of the shut-off valve 34.

Fig. 4 shows a circuit 1 according to the invention for an air-conditioning mode and for thermally treating the electrical storage device 40 during rapid charging of the electrical storage device 40. This mode of operation is used, for example, when the vehicle is stationary and charging is performed while the occupant remains in the vehicle. This operation mode allows the vehicle interior and the electrical storage device 40 to be cooled simultaneously, and the electrical storage device 40 has a greater cooling demand than in the running phase. The heating of the interior is performed by the fifth heat exchanger 12. The cooling of the electrical storage device 40 is performed by the first heat exchanger 13 and the second heat exchanger 17. The convergence point 6 receives a mixture of superheated and non-superheated refrigerant 47.

In the example of fig. 4, the refrigerant 47 flows as described in fig. 2 except for the first branch passage 4. The circulation in the first branch 4 will be described below. In the case of the other branches, and in the case of the main pipe 3, reference may be made to the description given with reference to fig. 2, which applies mutatis mutandis in detail.

In the first branch passage 4, the refrigerant 47 circulates and undergoes expansion by the first expansion member 16. Having subsequently been lowered to a low temperature and pressure accordingly, it exchanges heat within the first heat exchanger 13, while the heat transfer liquid 48 passes through the first heat exchanger 13. In the second branch 5, the refrigerant 47 circulates as described in fig. 2. Therefore, the electrical storage device 40 is cooled by the combined heat treatment of the first heat exchanger 13 and the second heat exchanger 17 to meet the increased cooling demand thereof.

The refrigerant 47 from the first branch 4 and the third branch 25 reaches the first junction point 19 before entering the accumulation device 15. Outside the accumulation device 15, the gaseous refrigerant 47 is mixed with the superheated refrigerant 47 coming from the second branch 5, which superheated refrigerant 47 has evaporated in the second heat exchanger 17.

In the example of fig. 4, the heat transfer liquid 48 circulates throughout the loop 14 for the heat transfer liquid 48 in order to cool the electrical storage device 40 by means of simultaneous operation of the first heat exchanger 13 and the second heat exchanger 17.

Fig. 5 shows the circuit 1 according to the invention operating in the interior heating mode during a driving phase.

In the example of fig. 5, the compression device 2 applies high pressure and high temperature to the refrigerant 47 in the main pipe 3. It is in this state that the refrigerant 47 passes through the fifth heat exchanger 12. The refrigerant 47 exchanges with the inner air flow FA while passing through the fifth heat exchanger 12. The fifth heat exchanger 12 is thus used as a condenser for the refrigerant 47. In this way, the interior air flow FA is heated and heats the vehicle interior.

The refrigerant 47 enters the second portion 36 of the main pipe 3 and the fifth branch 32 through the fourth joint point 33, and the shutoff valve 34 is closed.

In the second portion 36 of the main pipe 3, the main expansion member 9 expands the refrigerant 47, and the refrigerant 47 changes from high pressure and high temperature to low pressure and low temperature. Main heat exchanger 8, operating as an evaporator, allows refrigerant 47 to recover thermal energy from outside air stream FE.

At the third junction point 29, the refrigerant 47 reaches the first junction point 19 through the fourth branch 30, and the shutoff valve 31 is opened. The refrigerant 47 is actually sucked by the downstream compression device 2. Therefore, the refrigerant 47 does not flow along the third portion 37 of the main tube 3. The refrigerant 47 reaches the compression device 2 via the accumulation device 15.

In the example of fig. 5, the refrigerant 47 circulates through the first and

second portions

35 and 36 of the main pipe 3, through the fourth branch 30 and through the second portion 22 of the first branch 4. Due to the closure of the first expansion member 16 it does not circulate in the third portion 37 of the main leg nor in the first branch 4, and due to the closure of the second expansion member 18 it does not circulate in the second branch 5, and due to the closure of the third expansion member 28 it does not circulate in the third branch 25, and due to the closure of the shut-off valve 34 it does not circulate in the fifth branch 32.

Fig. 6 shows that during a driving phase, the circuit 1 according to the invention operates in a mode providing internal heating and a mode providing cooling of the portion 39 of the electric traction drive system. This operation mode thus allows both heating the vehicle interior and cooling the electrical storage device 40. According to the embodiment depicted in fig. 5, the heating of the vehicle interior is performed by the fifth heat exchanger 12. According to the embodiment described in fig. 2, the cooling of the electrical storage device 40 is performed by the second heat exchanger 17. The convergence point 6 receives a mixture of superheated and non-superheated refrigerant 47.

Differences compared to those listed in fig. 5 will be described below. In addition to these differences, the description of fig. 5 applies mutatis mutandis and reference may be made to the implementation of the invention according to fig. 6.

At the fourth junction point 33, the refrigerant 47 takes the fifth branch 32, and the shutoff valve 34 is opened. It then circulates in the second branch 5, as described in fig. 4, to which the invention described in fig. 6 can be implemented.

In the example of fig. 6, the refrigerant 47 circulates through the first and

second portions

35, 36 of the main pipe 3, through the fourth branch 30, through the second portion 22 of the first branch 4, through the first branch 32 and through the second branch 5. It does not circulate in the third portion 37 of the first branch 4 nor in the first branch 4 due to the closure of the first expansion member 16, and it does not circulate in the third branch 25 due to the closure of the third expansion member 28. The fourth joining point 33 is a point at which the refrigerant 47 is branched, and the merging point 6 is a point at which the refrigerant 47 is merged.

In the example of fig. 6, the heat transfer liquid 48 circulates at least in the main pipe 41 and the second pipe 44 so as to exchange heat between the refrigerant 47 and the heat transfer liquid 48.

Fig. 7 shows a second embodiment of a thermal management system 38 comprising a circuit 1 according to the invention. Differences compared to those listed in fig. 1 will be described below. In addition to these differences, the description of fig. 1 applies mutatis mutandis and reference may be made to the implementation of the invention according to fig. 7. The difference lies in the circuit 1 according to the invention and in the loop 14 for the heat transfer liquid 48. However, in other embodiments, any of these differences may be found alone.

In the example of fig. 7, the circuit 1 according to the invention comprises an internal heat exchanger 60 with two

channels

61, 62.

The low-pressure channel 61 is preferably located in the main pipe 3 between the convergence point 6 and the compression device 2. Alternatively, the low pressure channel 61 is located between the accumulation device 15 and the convergence point 6.

The high-pressure passage 62 is located in the main pipe 3 between the supercooling unit 10 and the convergence point 7, more specifically, between the check valve 11 and the divergence point 7.

In order to make fig. 7 easier to understand, the low-pressure passage 61 and the high-pressure passage 62 are not clearly connected in fig. 7. It must be understood, however, that the low-pressure channel 61 and the high-pressure channel 62 form part of one and the same internal heat exchanger 60, enabling heat exchange between the low-pressure refrigerant circulating in the low-pressure channel 61 and the high-pressure refrigerant circulating in the high-pressure channel 62.

In the example of fig. 7, the first heat exchanger 13 and the second heat exchanger 17 are assigned to the thermal treatment of the same portion 39 of the electric traction drive system of the vehicle, i.e. the electrical storage device 40. The loop 14 for heat transfer liquid 48 shown in fig. 7 enables the thermal treatment of the other two parts 39 of the electric traction drive system of the vehicle, namely an electric motor 49 and an electronic control unit 50 for controlling the electric motor 49. To supplement the cooling that can be provided by the first heat exchanger 13 and the second heat exchanger 17, the electrical storage device 40 enjoys additional cooling, which is achieved by the radiator 51 and the supercooling unit 10 on the front face of the vehicle. The radiator 51 is configured to pass therethrough an outside air flow FE outside the vehicle. With respect to this external air stream FE, the radiator 51 is located upstream of the main heat exchanger 8.

The heat sink 51 is capable of generating two temperature levels for the heat transfer liquid therein. To this end, the heat sink 51 includes an inlet 52, a first outlet 53 and a second outlet 54, which are parallel to each other. The first outlet 53 is capable of delivering heat transfer liquid at a first temperature level and the second outlet 54 is capable of delivering heat transfer liquid at a second temperature level different from the first temperature level. Thanks to the first temperature level, the first outlet 53 is able to supply the electric motor 49. Thanks to the second temperature level, the second outlet 54 is able to supply the electrical storage device 40 and the electronic unit 50.

The loop 14 for heat transfer liquid 48 includes a third connection point 55 and a fourth connection point 56. The third connection point 55 is a point for diverting the heat transfer liquid 48 such that it is directed towards the second connection point 46 on the one hand and towards the electronics unit 50 on the other hand. The fourth connection point 56 is a point intended to converge the heat transfer liquid 48 from the first connection point 45 on the one hand and the electric motor 49 on the other hand.

In order to circulate the heat transfer liquid 48 from the first outlet 53 of the heat sink 51, the loop 14 for the heat transfer liquid 48 is provided with additional displacement means 57 for displacing the heat transfer liquid. An additional displacement device 57 is located between the first outlet 53 and the electric motor 49. For example it is a pump.

Between the first outlet 53 of the heat sink 51 and the additional displacement means 57 for displacing the heat transfer liquid, there is a fifth connection point 58. The fifth connection point 58 is a convergence area that enables the heat transfer liquid 48 from the first outlet 53 and the heat transfer liquid from the electronics unit 50 to converge.

The first conduit 43 includes a three-way valve 59. The three-way valve 49 is the point where the heat transfer liquid 48 is dispersible. The heat transfer liquid 49 is circulated through the circulation inducing means 52, and the circulation inducing means 52 imposes the direction of circulation of the heat transfer liquid 49. In particular, the first heat exchanger 13 and the second heat exchanger 17 are located upstream of the electrical storage device 40 from the viewpoint of the heat transfer liquid 49. Therefore, the heat transfer liquid 49 from the first connection point 45 can be supplied to the three-way valve 59 due to the flow direction in which the device 42 applies to cause the flow of the heat transfer liquid 49, and the three-way valve 59 itself can convey the heat transfer liquid 48 to the first heat exchanger 13 on the one hand and the heat transfer liquid 48 to the fourth connection point 56 on the other hand. The three-way valve 59 has a shut-off function, capable of preventing or allowing one and/or the other of these deliveries.

As can be understood from the foregoing, the invention thus makes it possible to simply ensure, without excessive consumption and reduced noise levels: cooling a portion of an electric traction drive system of a vehicle, such as an electrical storage device configured to supply electrical energy to an electric drive motor of the vehicle; and heat treating the vehicle interior by cooling the interior airflow sent into the vehicle interior. The coefficient of performance of the circuit is thus improved, in particular during fast charging and at the same time cooling of the vehicle interior mode.

The invention is in no way limited to the arrangements and constructions described and illustrated herein, but extends to any equivalent arrangement or construction and any technically operable combination of such arrangements. In particular, the structure of the refrigerant circuit may be modified without departing from the invention, as long as it finally fulfils the functions described in this document.

Claims

1. Refrigerant circuit (1) for a vehicle, the circuit (1) comprising at least a main pipe (3), a first branch (4), a second branch (5) and a third branch (25), all three branches being in series with said main pipe (3), said main pipe (3) comprising at least a compression device (2) for compressing said refrigerant (47) and a main heat exchanger (8) arranged to be crossed by an external air Flow (FE) outside the interior of the vehicle, said first branch (4) comprising at least a first heat exchanger (13) thermally coupled to a loop (14) for a heat transfer liquid (48) and an accumulation device (15) for accumulating said refrigerant (47), said second branch (5) comprising at least a second heat exchanger (17) thermally coupled to said loop (14) for a heat transfer fluid (48), -said third branch (25) comprises at least a third heat exchanger (26) designed to be crossed by an internal air Flow (FA) sent to the vehicle interior, characterized in that said first branch (4) and said second branch (5) are parallel and meet at a confluence point (6) located between said accumulation device (15) and said compression device (2), and in that said first branch (4) and said third branch (25) meet at a first junction point (19) located between said first heat exchanger (13) and said accumulation device (15).

2. The circuit (1) according to claim 1, wherein the main pipe (3) extends between the convergence point (6) and a bifurcation point (7), the bifurcation point (7) being the point at which the first branch (4) and the second branch (5) diverge.

3. The circuit (1) according to claim 2, wherein the main pipe (3) comprises a subcooling unit (10) between the main heat exchanger (8) and the bifurcation point (7).

4. Circuit (1) according to claim 3, wherein said subcooling unit (10) is a fourth heat exchanger designed to be crossed by said external air Flow (FE) outside the vehicle interior and installed so that it crosses said fourth heat exchanger before crossing said main heat exchanger (8).

5. The circuit (1) according to any one of the preceding claims, wherein the first branch (4) comprises a first junction (19), the second branch (5) comprises a second junction (20), and a third branch (25) of the circuit (1) extends between the first junction (19) and the second junction (20).

6. Circuit (1) according to claim 5, wherein the main pipe (3) comprises a fifth heat exchanger (12) between the compression device (2) and the main heat exchanger (8), the fifth heat exchanger (12) being designed to pass through this fifth heat exchanger (12) the internal air Flow (FA) sent to the vehicle interior.

7. Circuit (1) according to claims 2 and 5, wherein the main pipe (3) comprises a third junction (29) between the main heat exchanger (8) and the bifurcation (7), a fourth branch (30) extending between the third junction (29) and the first junction (19), the fourth branch (30) comprising at least one shut-off valve (31).

8. The circuit (2) according to any one of claims 2 to 7, comprising a fifth branch (32) connecting the main pipe (3) to the bifurcation point (7), the fifth branch (32) comprising at least one shut-off valve (34).

9. The circuit (1) according to any one of the preceding claims, wherein the first heat exchanger (13) is configured to generate a thermal power greater than a thermal power of the second heat exchanger (17).

10. The circuit (1) according to any one of the preceding claims in combination with claim 3, comprising an internal heat exchanger (60) having two channels (61,62), a low-pressure channel (61) being located in the main pipe (3) between the convergence point (6) and the compression device (2), and a high-pressure channel (62) being located in the main pipe (3) between the subcooling unit (10) and the bifurcation point (7).

11. The circuit (1) according to any one of the preceding claims in combination with claim 3, comprising an internal heat exchanger (60) having two channels (61,62), a low pressure channel (61) being located between the accumulation means (15) and the convergence point (6) and a high pressure channel (62) being located in the main conduit (3) between the subcooling unit (10) and the bifurcation point (7).

12. System (38) for the thermal treatment of a vehicle, comprising a refrigerant circuit (1) for a refrigerant (47) and a loop (14) for a heat transfer liquid (48) according to any one of the preceding claims, the loop (14) being thermally coupled to the refrigerant circuit (1) for a refrigerator fluid (47) via a first heat exchanger (13) and a second heat exchanger (17), the first heat exchanger (13) and the second heat exchanger (17) being assigned to the thermal treatment of at least one identical part (39) of an electric traction drive of the vehicle.